1. Field of the Invention
This invention relates to liquid dispensing nozzle assemblies which incorporate a vapor recovery collecting means. More particularly, it relates to a means for retaining the spring biased vapor recovery bellows incorporated on a liquid dispensing nozzle in a collapsed position to allow the use of the liquid dispensing nozzle assembly to fill containers not designed to accommodate and seal the distal end of a vapor recovery bellows.
2. Prior Art
In their efforts to meet the air quality standards set by the United States Government and various State agencies, many urban areas of the United States and more specifically the entire state of California, now require retailers of gasoline and some other hydrocarbon liquids to fit the liquid dispensing nozzle with a vapor recovery system. To that end, retailers of gasoline and other easily evaporated hydrocarbon based liquids, in areas of the United States with government mandated vapor recovery requirements, have fitted their liquid dispensing pumps with nozzles incorporating a means to seal and provide a recovery passage around the liquid or fuel dispensing nozzle and the mouth of a fuel tank to be filled by the liquid dispensing nozzle.
U.S. Pat. No. 3,866,636 (Lasater), U.S. Pat. No. 3,840,055 (Worst) are common examples of the numerous vapor collection fuel nozzles currently in use which operate in similar manners through the use of a vapor collection means consisting of a flexible bellows sleeve which surrounds the spout or liquid outlet means of the dispensing nozzle and is spring biased to extend near the fuel outlet means. During the fueling operation the flexible bellows sleeve is sealed to the opening or fillpipe of the fuel tank. The result being that as the tank is filled with fuel by the dispensing nozzle, the vapors which normally would escape into the earth's atmosphere using a non vapor recovery system, are trapped in the vapor collection means and returned to the reservoir tank from which the liquid was pumped. As taught in U.S. Pat. No. 3,840,055 (Wostl), when not in use, the vapor recovery system of the nozzle is commonly sealed off from the outside atmosphere through the use of an annular sealing ring mounted on the filling tube portion of the nozzle which provides an shoulder upon which the flexible bellows seals internally trapping vapors inside the recovery system. The annular ring doubles as a retaining device which clips under the lip of the fueling pipe when inserted into the fueling pipe during fueling of the tank. There are similar such rings, knobs, and clips on the majority of fuel dispensing nozzles in use in the United States whether used for retaining of the nozzle in the fill pipe of the fuel tank or for sealing the vapor recovery system when the nozzle is not in use.
One problem which has occurred in attempting to minimize vapor loss during the dispensing of liquid by the dispensing nozzle involves the fact that a constant pressure to sufficiently compress the bellows portion against the spring bias must be maintained between the front lip of the vapor recovery bellows and the top of the fillpipe of the fuel tank. If the user fails to maintain pressure to adequately compress the vapor recovery bellows to maintain a seal with the top of the fuel tank fillpipe the fuel pumping device which feeds the fueling nozzle on many such vapor recovery nozzles, will sense the loss of compression through a sensing means and will cause the pumping device for the liquid to cease to operate. Many users of such vapor recovery nozzles, especially in the modern era of self service fueling stations, lack the physical strength to maintain the pressure required for continued retraction of the spring loaded bellows vapor recovery device for a sufficient time to fill their fuel tanks.
Another problem encountered by users of vapor recovery fueling systems involves the location of fillpipe. Automotive fuel tank fillpipes are situated in a great many locations on the hundreds of different vehicle models available in the United States. Some locations are well designed to use the bellows style vapor recovery nozzles while others make it almost impossible for the user to insert the fueling nozzle into the fuel tank fillpipe and maintain the required pressure to retract the bellows and maintain a seal between the fillpipe and the vapor recovery bellows sufficient to allow the pump to operate properly.
A still further problem involves the use of a vapor recovery fuel dispensing nozzle on a fuel tank or container not designed for such a fuel dispensing system. Many older vehicles in the Untied States were built prior the more modern stringent vapor recovery standards now in place. Consequently the fuel tanks on such vehicles were not designed by their manufacturers for a vapor recovery means which seals over the fillpipe. The result of the use of a vapor recovery fuel dispensing nozzle on such fillpipes can be the formation of a vacuum in the fuel tank from the vapor recovery bellows wish attaches to the fillpipe of the fuel tank and removes atmospheric pressure from the tank, or, more seriously, the formation of high pressure in the fuel tank as a result of the pumping of liquid into the closed fuel tank and the improper seal of the vapor recovery bellows over the fill pipe which can cause a blockage for escaping gasses. This can result in a backwash of fuel on the user and the vehicle upon the removal of the nozzle, or, more seriously the complete rupture of the fuel tank and the contents of highly flammable liquids being spewed from the tank.
A further and most vexing problem encountered with the use of vapor recovery type fuel nozzles occurs when the user attempts to fill common portable gasoline container or a portable spring loaded safety fuel container. The most common of such containers have thin walls, and a one to five gallon capacity. Such portable containers are used to transport fuel to small gasoline engine or diesel engine powered devices such as lawn mowers and generators. Such portable containers are capped by a simple screw on type cap or in the case of safety spring loaded containers, a spring loaded cap must be removed by gripping a trigger mechanism by hand on the can which raises the cap off the fillpipe of the fuel container.
Vapor recovery nozzles, when used with portable fuel tanks and other fuel containers not designed for use with a vapor recovery nozzle, pose the user with a dilemma. Most modern fueling nozzles have a sensor located at their tip which shuts off the fuel pump when that senor senses liquid touching the tip of the nozzle. This is a safety device to insure the tank does not overflow during fueling. To maintain the bellows in the collapsed position required by bellows senors in the nozzle requires the user to insert the tip of the nozzle into the small portable fuel container to a point where the nozzle tip is so far inside the container that the nozzle tip liquid senor shuts the nozzle off when the fuel rises in the container and touches the nozzle tip. Unfortunately, on small one and two gallon containers, the container is only partially full when the liquid rises to the point the nozzle tip sensor erroneously signals the container is full and shuts off the pump. The user at this point, if he has sufficient body strength, can collapse the bellows by hand pressure and try to hold the nozzle tip above the container in a steady state for a sufficient time to fill the container. However, most gas station patrons lack sufficient body strength to accomplish this strenuous task for sufficient time to fuel the container especially in the awkward or contorted body position it requires.
On the aforementioned spring loaded safety containers, the user is especially challenged as he must grip the trigger mechanism on the can with one hand to open the container fillpipe while at the same time he must push the bellows against the fillpipe of the safety can with the other hand with sufficient pressure for the bellows senor to allow fueling. Safety cans too suffer inadequate filling when the fuel rises inside the container to a point that the nozzle tip liquid sensor erroneously shuts off the pump.
A further problem can develop on such portable fuel containers if no venting system is designed into such a container to allow for the vapor recovery system on the fueling nozzle to extract vapors from the atmosphere contained in the container. The result again is frustration of the user with the resulting cease of operations by the pump, or the collapse of the walls of the small container from the negative atmosphere which can develop.
A more serious problem which occurs using portable fuel containers with vapor recovery nozzles is the possible rupture of the container wall should high pressure develop as a result of the fuel being pumped into the container and the bellows improperly sealing around an ill designed fillpipe and blocking escaping gases. The resulting failure to allow the escape of any vapors or air from the container can cause the build up of internal atmospheric pressure in the container resulting in the rupture of its walls or the spewing of a geyser of fuel on the user when the fueling nozzle is removed.
Another problem which develops in the fueling of motorized vehicles using a vapor recovery fuel nozzles occurs in the fueling of boats and other motor powered vehicles with a fuel tank fillpipe not designed to accommodate the bellows style vapor recovery means surrounding the fuel nozzle tip of such fuel dispensing devices. As an example, pleasure boats normally have a very small diameter fillpipe aperture which does not accommodate the vapor recovery bellows in an adequate fashion to allow proper ventilation of the fuel tank during the fueling operation. Depending on how the fueling nozzle tip is inserted and how the bellows comes to rest on the hull, the result can be a ruptured fillpipe from internal tank pressure which can develop or backwash of gasoline upon the user and the boat upon the removal of the fuel nozzle, or, the collapse of the tank if a vacuum develops from the bellows extraction of tank atmosphere.